The invention relates to a method of forming a headliner having an integrally formed energy management region and/or support region.
U.S. Pat. No. 5,683,796 discloses a method of making a headliner that includes spraying a layer of foamable material, such as liquid polyurethane, on a cover layer. The foamable material is permitted to free-rise or expand so that it has a generally constant density throughout. Consequently, this method is not useful to produce a headliner having different densities at different locations on the headliner. Furthermore, because the foamable material has a uniform composition, this method is also not useful to produce a headliner with multiple and distinct features, such as high strength support regions and/or energy management regions.
A prior method of making a headliner assembly having energy management members, such as head impact pads, includes forming the pads separately from the headliner. The pad forming process includes molding a block of foam, cutting the block into rectangular panels, die-cutting the panels, and compression molding the panels to form the pads. The pads are then attached to a preformed headliner using assembly dies and an adhesive. Because of the multiple steps involved with forming the pads and attaching the pads to the headliner, this method is time consuming and costly. Furthermore, because the pads are die-cut from rectangular panels, this method also results in significant waste.
U.S. Pat. No. 5,845,458 discloses another method of making a headliner having deformable foam inserts disposed on side edges of the headliner. The method includes positioning a cover layer, a foam panel, and preformed rectangular foam inserts in a mold, and draping a flexible backing layer over the foam panel and foam inserts. Suitable adhesives are also positioned between the cover layer and the foam panel, and between the foam panel and the foam inserts. The mold is then closed to compression mold the foam panel and foam inserts, as well as to stiffen the backing layer. Similar to the above method, however, this method involves multiple steps for forming the inserts and attaching the inserts to the remainder of the headliner.
It would be desirable to provide an improved method of incorporating energy management and/or support characteristics into a headliner structure.
The invention overcomes the shortcomings of the prior art by providing an improved method of forming a headliner using a lap mat having an integrally formed energy management region and/or support region.
Under the invention, a method of forming a headliner includes providing a lap mat including a first region having a first material composition, and a second region having a second material composition different than the first material composition, wherein the second region is configured as at least one of an energy management region and a support region; positioning the mat between two mold sections of a mold; and moving at least one of the mold sections toward the other mold section to shape the mat into a desired shape.
The method may also include differentially heating the mat such that at least a portion of the second region is heated to a different temperature than the first region. For example, the second region may be heated to a higher temperature than the first region, such that the second region may experience more crystallization and/or be compressed more during the manufacturing process than the first region. As a result, the second region may be provided with a greater density than the first region.
Further under the invention, a method of forming a headliner includes providing a cross-lap mat including a major region having a first fiber composition, and a plurality of localized regions having a second fiber composition different than the first fiber composition; heating the mat; positioning the mat between two mold sections of a mold; and moving at least one of the mold sections toward the other mold section to shape the mat into a desired shape and thereby form the headliner, such that at least one of the localized regions is positioned proximate a peripheral edge of the headliner to provide energy management, and another of the localized regions is positioned proximate a central portion of the headliner to provide resistance to sag.
A method of forming a lap mat for use in a subsequent molding operation to form a headliner is also provided. The method includes forming a first continuous layer of fibers; folding the first continuous layer to form a plurality of first fibrous layers; and binding the first fibrous layers together; wherein the first fibrous layers cooperate to define a first region having a first fiber composition, and a second region having a second material composition different than the first fiber composition.
Binding the first fibrous layers together may include needle punching the first fibrous layers together. Alternatively, binding the first fibrous layers together may include heating the first fibrous layers and forcing the first fibrous layers together.
The method of forming the lap mat may further include positioning additional material between at least two of the first fibrous layers, such that the additional material cooperates with the first fibrous layers to define the second region.
The method of forming the lap mat may also include introducing a second fibrous layer between two first fibrous layers, wherein the second fibrous layer cooperates with the first fibrous layers to define the first and second regions. Furthermore, fibers of the first fibrous layers may be generally oriented in a first direction, and fibers of the second fibrous layer may be generally oriented in a second direction different than the first direction.
A method of forming a cross-lap mat for use in a subsequent molding operation to form a headliner includes forming a first continuous layer of fibers; forming a second continuous layer of fibers; folding the first continuous layer to form a plurality of first fibrous layers; folding the second continuous layer to form a plurality of second fibrous layers; joining the first and second fibrous layers together such that at least one of the second fibrous layers is disposed between two first fibrous layers, and binding the first and second fibrous layers together to form the mat; wherein the first and second fibrous layers cooperate to define a first major region having a first fiber composition, and a second localized region having a second material composition different than the first fiber composition, and wherein fibers of the first fibrous layers are oriented generally in a first direction, and fibers of the second fibrous layers are oriented generally in a second direction different than the first direction.
These and other objects, features and advantages of the invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in conjunction with the accompanying drawings.